Roaring Sands of the Kalahari Desert

Manawatu Times, Volume 62, Issue 132, 5 June 1937, Page 10

Roaring Sands of the Kalahari Desert

STRANGE PHENOMENON JOHANNESBURG, April 27. South Africa has an area of roaring sands which is one of the most remarkable in the world. This area is on the farm Witsands, near the south-eastern border of the Kalahari desert. There, a patch pf whitish dunes about a mile wide and six miles long, stands out above the surrounding desert so that it is clearly visible from an aeroplane 80 : miles away and 2000 ft up. These roaring sands were recently visited by Mr A. D. Lewis, director of Irrigation in the Union. The sound of people sliding down the 100 ft slope which borders this area was clearly heard 600 yards away. Even when a dog ran across the dunes a rumbling sound could be heard. Composed of Quartz Grains The sands roared at every footstep. If a Auger was pushed gently into them tho sands roared. They roared again an octave higher when the finger was withdrawn. If a hole was scraped in the side of a dune the sound of sand falling into it ,at a speed of half a foot a second, produced a humming sound like an aeroplane in'steady flight. Mr Lewis and his assstants carried out extensive experiments both in the Kalahari and in laboratories in Pretoria to determine the cause of the noise. They found that the roaring dunes were composed of quartz grains which were nearly all of a uniform size. This meant that there was little fine material to retain what moisture there was in the Kalahari, and dryness, it became apparent, was an essential factor in production of the roar. Laboratory Demonstrations The transference of the sand to a moister climate such as that at Pretoria, and the handling of it, destroyed the roar. But they found that it could bo restored by heating the sand in an oven. The roar disappeared again within a few minutes unless the sand was kept in airtight containers. Samples of the sand, sealed in glass jars, were shown to members of the Geographical Society, who satisfied themselves about the noise, felt the vibrations as the sand was poured through an hour glass made by joining two fruit jars together, and heard the hum, like that of a trolley bus when accelerating, as the sand was poured through this glass.